Some gestures stay in the mind as sharply as the most memorable phrase.
Simone Pika has published a useful review of ape gestures in the First Language journal, “Gestures of apes and pre-linguistic human children: Similar or different?” (abstract here). I don’t suppose it will bowl anyone over with its finding that while both apes and children can make imperative gestures (e.g., give me food) human children, but not apes, also make “gestures for declarative purposes to direct the attention of others to some third entity, simply for the sake of sharing interest in it or commenting on it” [p. 131]. But when all the different sorts of ape gestures are drawn together it is quite evident that the really peculiar aspect of speech is the presence of what this blog calls the speech triangle, and what Pika calls triadic form. That is, humans are peculiar in having a speaker, a listener, and an outside topic.
Dyadic gestures—actions used to attract attention to the actor—are common enough among apes, but informative triads among apes in the wild are almost unknown. (The one exception: a free bonobo once was observed probably pointing out human observers hiding in the bushes.) Pika says a little ambiguously, “It is therefore quite puzzling why only human beings comment on outside entities simply to share experiences.” I would put it a little differently. It’s quite puzzling how we came to comment on outside entities when no other animal seems to share the need. Once we can give a solid explanation for that puzzle, we will have come a long way in understanding why humans are different.
Pika proposes that possibly the “propensity [to comment on outside entities] derived from the need to create a new medium for social bonding triggered by an increase of group size, superseding grooming as a servicing tool for social relationships.”  That’s Robin Dunbar’s old thesis, and I am surprised to see it turn up here because the objection has had plenty of time to get around. Babbling and singing together provide emotional links without having to do all the rebuilding of the brain and sociology that meaningful speech requires. So, if all speech arose to do was fill in for grooming, why do we speak meaningfully?
More useful is the way Pika’s article forces attention on the difference between ape and human gestures while providing a link between the two. Here is the critical difference:
Many human gestures are … used to direct the attention and mental states of others to outside entities… Apes also gesture… but use these communicative means mainly as effective procedures in dyadic interactions to request action from others. [pp 131-132]
Because of the thoroughness of the Pika’s review I feel confident in taking the dyadic/triadic distinction as settled. A human peculiarity is our interest in and attention to neutral topics that have nothing to do with the brute facts of survival. (“Brute facts” is a handy term I heard Chris Knight use at the Evolang conference.)
Pika goes on:
Many of these [ape] gestures are used intentionally and are clearly learned. Thus, this review provides further support for the hypothesis that the gestural modality of our closest living relatives might have been the crucial modality of our closest living relatives within which the evolutionary precursors of symbolic communication evolved. [p. 132]
I have long been skeptical of the idea that sign language preceded speech, chiefly on the grounds that it replaces one hard problem (the origins of speech) with another (the origins of sign language); however, if we take gesture more generally Pika along with Susan Goldin-Meadow at Evolang (See: Gesture Adds More than Structure) have persuaded me that directive and illustrative gestures have been with us all along and that the idea of speech as vocalization without gesture is naïve. Gesture is another set of cues that are missing from written language.
Sound and gesture together, by the way, are older than speech. In Pika’s accounts—although she does not dwell on this point—the apes are routinely making noises while they gesture. The sounds in these cases seem to be offered as attention getters, the equivalent of saying, “Ahem,” and holding out one’s hand to a person eating from a bag of M&Ms.
One can imagine this kind of progression:
- An ape gesturing imperatively while attracting attention vocally. (Routine dyadic communicative interaction)
- Australopithecus/Homo attracting attention vocally while pointing to an outside matter of interest. (Triadic interaction)
- Homo adding meaning to vocal signal while gesturing about an outside matter of interest. (Full speech triangle)
Both of these steps involve important breaks. The second step requires some sort of profound sociological shift, and the third follows only from a shift in the nature of vocalizations. None the less, it looks possible (maybe even likely) that the first pilot of attention toward a neutral topic was gestural pointing rather than a spoken word.